This study is determining the frequency and severity of hyperhomocysteinemia in the kidney transplant population. The diagnostic sensitivities of fasting homocysteine and post-methionine homocysteine will be determined. This study will alsp attempt to define effective vitamin therapies for hyperhomocysteinemia in this population and thereby reduce cardiovascular risk. Patients will be assigned to one of six treatment groups based on fasting and post-methionine homocysteine levels. The response to therapy will be assessed at 6 weeks, 12 weeks, and one year. Vitamin therapy will be adjusted in an effort to normalize homocysteine levels.